from __future__ import (absolute_import, division, print_function,
                        unicode_literals)
import six

import os
import re
import signal
import sys
from six import unichr

import matplotlib

from matplotlib.backend_bases import FigureManagerBase
from matplotlib.backend_bases import FigureCanvasBase
from matplotlib.backend_bases import NavigationToolbar2

from matplotlib.backend_bases import cursors
from matplotlib.backend_bases import TimerBase
from matplotlib.backend_bases import ShowBase

from matplotlib._pylab_helpers import Gcf
from matplotlib.figure import Figure

from matplotlib.widgets import SubplotTool
import matplotlib.backends.qt_editor.figureoptions as figureoptions

from .qt_compat import (QtCore, QtGui, QtWidgets, _getSaveFileName,
                        __version__, is_pyqt5)
from matplotlib.backends.qt_editor.formsubplottool import UiSubplotTool

backend_version = __version__

# SPECIAL_KEYS are keys that do *not* return their unicode name
# instead they have manually specified names
SPECIAL_KEYS = {QtCore.Qt.Key_Control: 'control',
                QtCore.Qt.Key_Shift: 'shift',
                QtCore.Qt.Key_Alt: 'alt',
                QtCore.Qt.Key_Meta: 'super',
                QtCore.Qt.Key_Return: 'enter',
                QtCore.Qt.Key_Left: 'left',
                QtCore.Qt.Key_Up: 'up',
                QtCore.Qt.Key_Right: 'right',
                QtCore.Qt.Key_Down: 'down',
                QtCore.Qt.Key_Escape: 'escape',
                QtCore.Qt.Key_F1: 'f1',
                QtCore.Qt.Key_F2: 'f2',
                QtCore.Qt.Key_F3: 'f3',
                QtCore.Qt.Key_F4: 'f4',
                QtCore.Qt.Key_F5: 'f5',
                QtCore.Qt.Key_F6: 'f6',
                QtCore.Qt.Key_F7: 'f7',
                QtCore.Qt.Key_F8: 'f8',
                QtCore.Qt.Key_F9: 'f9',
                QtCore.Qt.Key_F10: 'f10',
                QtCore.Qt.Key_F11: 'f11',
                QtCore.Qt.Key_F12: 'f12',
                QtCore.Qt.Key_Home: 'home',
                QtCore.Qt.Key_End: 'end',
                QtCore.Qt.Key_PageUp: 'pageup',
                QtCore.Qt.Key_PageDown: 'pagedown',
                QtCore.Qt.Key_Tab: 'tab',
                QtCore.Qt.Key_Backspace: 'backspace',
                QtCore.Qt.Key_Enter: 'enter',
                QtCore.Qt.Key_Insert: 'insert',
                QtCore.Qt.Key_Delete: 'delete',
                QtCore.Qt.Key_Pause: 'pause',
                QtCore.Qt.Key_SysReq: 'sysreq',
                QtCore.Qt.Key_Clear: 'clear', }

# define which modifier keys are collected on keyboard events.
# elements are (mpl names, Modifier Flag, Qt Key) tuples
SUPER = 0
ALT = 1
CTRL = 2
SHIFT = 3
MODIFIER_KEYS = [('super', QtCore.Qt.MetaModifier, QtCore.Qt.Key_Meta),
                 ('alt', QtCore.Qt.AltModifier, QtCore.Qt.Key_Alt),
                 ('ctrl', QtCore.Qt.ControlModifier, QtCore.Qt.Key_Control),
                 ('shift', QtCore.Qt.ShiftModifier, QtCore.Qt.Key_Shift),
                 ]

if sys.platform == 'darwin':
    # in OSX, the control and super (aka cmd/apple) keys are switched, so
    # switch them back.
    SPECIAL_KEYS.update({QtCore.Qt.Key_Control: 'super',  # cmd/apple key
                         QtCore.Qt.Key_Meta: 'control',
                         })
    MODIFIER_KEYS[0] = ('super', QtCore.Qt.ControlModifier,
                        QtCore.Qt.Key_Control)
    MODIFIER_KEYS[2] = ('ctrl', QtCore.Qt.MetaModifier,
                        QtCore.Qt.Key_Meta)


def fn_name():
    return sys._getframe(1).f_code.co_name

DEBUG = False

cursord = {
    cursors.MOVE: QtCore.Qt.SizeAllCursor,
    cursors.HAND: QtCore.Qt.PointingHandCursor,
    cursors.POINTER: QtCore.Qt.ArrowCursor,
    cursors.SELECT_REGION: QtCore.Qt.CrossCursor,
    }


def draw_if_interactive():
    """
    Is called after every pylab drawing command
    """
    if matplotlib.is_interactive():
        figManager = Gcf.get_active()
        if figManager is not None:
            figManager.canvas.draw_idle()

# make place holder
qApp = None


def _create_qApp():
    """
    Only one qApp can exist at a time, so check before creating one.
    """
    global qApp

    if qApp is None:
        if DEBUG:
            print("Starting up QApplication")
        app = QtWidgets.QApplication.instance()
        if app is None:
            # check for DISPLAY env variable on X11 build of Qt
            if is_pyqt5():
                try:
                    from PyQt5 import QtX11Extras
                    is_x11_build = True
                except ImportError:
                    is_x11_build = False
            else:
                is_x11_build = hasattr(QtGui, "QX11Info")
            if is_x11_build:
                display = os.environ.get('DISPLAY')
                if display is None or not re.search(r':\d', display):
                    raise RuntimeError('Invalid DISPLAY variable')

            qApp = QtWidgets.QApplication(["matplotlib"])
            qApp.lastWindowClosed.connect(qApp.quit)
        else:
            qApp = app

    if is_pyqt5():
        qApp.setAttribute(QtCore.Qt.AA_UseHighDpiPixmaps)


class Show(ShowBase):
    def mainloop(self):
        # allow KeyboardInterrupt exceptions to close the plot window.
        signal.signal(signal.SIGINT, signal.SIG_DFL)
        global qApp
        qApp.exec_()

show = Show()


def new_figure_manager(num, *args, **kwargs):
    """
    Create a new figure manager instance
    """
    thisFig = Figure(*args, **kwargs)
    return new_figure_manager_given_figure(num, thisFig)


def new_figure_manager_given_figure(num, figure):
    """
    Create a new figure manager instance for the given figure.
    """
    canvas = FigureCanvasQT(figure)
    manager = FigureManagerQT(canvas, num)
    return manager


class TimerQT(TimerBase):
    '''
    Subclass of :class:`backend_bases.TimerBase` that uses Qt timer events.

    Attributes
    ----------
    interval : int
        The time between timer events in milliseconds. Default is 1000 ms.
    single_shot : bool
        Boolean flag indicating whether this timer should
        operate as single shot (run once and then stop). Defaults to False.
    callbacks : list
        Stores list of (func, args) tuples that will be called upon timer
        events. This list can be manipulated directly, or the functions
        `add_callback` and `remove_callback` can be used.

    '''

    def __init__(self, *args, **kwargs):
        TimerBase.__init__(self, *args, **kwargs)

        # Create a new timer and connect the timeout() signal to the
        # _on_timer method.
        self._timer = QtCore.QTimer()
        self._timer.timeout.connect(self._on_timer)
        self._timer_set_interval()

    def _timer_set_single_shot(self):
        self._timer.setSingleShot(self._single)

    def _timer_set_interval(self):
        self._timer.setInterval(self._interval)

    def _timer_start(self):
        self._timer.start()

    def _timer_stop(self):
        self._timer.stop()


class FigureCanvasQT(QtWidgets.QWidget, FigureCanvasBase):

    # map Qt button codes to MouseEvent's ones:
    buttond = {QtCore.Qt.LeftButton: 1,
               QtCore.Qt.MidButton: 2,
               QtCore.Qt.RightButton: 3,
               # QtCore.Qt.XButton1: None,
               # QtCore.Qt.XButton2: None,
               }

    def __init__(self, figure):
        if DEBUG:
            print('FigureCanvasQt qt5: ', figure)
        _create_qApp()

        # NB: Using super for this call to avoid a TypeError:
        # __init__() takes exactly 2 arguments (1 given) on QWidget
        # PyQt5
        # The need for this change is documented here
        # http://pyqt.sourceforge.net/Docs/PyQt5/pyqt4_differences.html#cooperative-multi-inheritance
        super(FigureCanvasQT, self).__init__(figure=figure)
        self.figure = figure
        self.setMouseTracking(True)
        w, h = self.get_width_height()
        self.resize(w, h)

        # Key auto-repeat enabled by default
        self._keyautorepeat = True

    @property
    def _dpi_ratio(self):
        # Not available on Qt4 or some older Qt5.
        try:
            return self.devicePixelRatio()
        except AttributeError:
            return 1

    def get_width_height(self):
        w, h = FigureCanvasBase.get_width_height(self)
        return int(w / self._dpi_ratio), int(h / self._dpi_ratio)

    def enterEvent(self, event):
        FigureCanvasBase.enter_notify_event(self, guiEvent=event)

    def leaveEvent(self, event):
        QtWidgets.QApplication.restoreOverrideCursor()
        FigureCanvasBase.leave_notify_event(self, guiEvent=event)

    def mouseEventCoords(self, pos):
        """
        Calculate mouse coordinates in logical pixels.

        Qt5 and Matplotlib use logical pixels, but the figure is scaled to
        physical pixels for rendering. Also, the origin is different and needs
        to be corrected.
        """
        x = pos.x()
        # flip y so y=0 is bottom of canvas
        y = self.figure.bbox.height / self._dpi_ratio - pos.y()
        return x, y

    def mousePressEvent(self, event):
        x, y = self.mouseEventCoords(event.pos())
        button = self.buttond.get(event.button())
        if button is not None:
            FigureCanvasBase.button_press_event(self, x, y, button,
                                                guiEvent=event)
        if DEBUG:
            print('button pressed:', event.button())

    def mouseDoubleClickEvent(self, event):
        x, y = self.mouseEventCoords(event.pos())
        button = self.buttond.get(event.button())
        if button is not None:
            FigureCanvasBase.button_press_event(self, x, y,
                                                button, dblclick=True,
                                                guiEvent=event)
        if DEBUG:
            print('button doubleclicked:', event.button())

    def mouseMoveEvent(self, event):
        x, y = self.mouseEventCoords(event)
        FigureCanvasBase.motion_notify_event(self, x, y, guiEvent=event)
        # if DEBUG: print('mouse move')

    def mouseReleaseEvent(self, event):
        x, y = self.mouseEventCoords(event)
        button = self.buttond.get(event.button())
        if button is not None:
            FigureCanvasBase.button_release_event(self, x, y, button,
                                                  guiEvent=event)
        if DEBUG:
            print('button released')

    def wheelEvent(self, event):
        x, y = self.mouseEventCoords(event)
        # from QWheelEvent::delta doc
        if event.pixelDelta().x() == 0 and event.pixelDelta().y() == 0:
            steps = event.angleDelta().y() / 120
        else:
            steps = event.pixelDelta().y()

        if steps != 0:
            FigureCanvasBase.scroll_event(self, x, y, steps, guiEvent=event)
            if DEBUG:
                print('scroll event: delta = %i, '
                      'steps = %i ' % (event.delta(), steps))

    def keyPressEvent(self, event):
        key = self._get_key(event)
        if key is None:
            return
        FigureCanvasBase.key_press_event(self, key, guiEvent=event)
        if DEBUG:
            print('key press', key)

    def keyReleaseEvent(self, event):
        key = self._get_key(event)
        if key is None:
            return
        FigureCanvasBase.key_release_event(self, key, guiEvent=event)
        if DEBUG:
            print('key release', key)

    @property
    def keyAutoRepeat(self):
        """
        If True, enable auto-repeat for key events.
        """
        return self._keyautorepeat

    @keyAutoRepeat.setter
    def keyAutoRepeat(self, val):
        self._keyautorepeat = bool(val)

    def resizeEvent(self, event):
        w = event.size().width() * self._dpi_ratio
        h = event.size().height() * self._dpi_ratio
        if DEBUG:
            print('resize (%d x %d)' % (w, h))
            print("FigureCanvasQt.resizeEvent(%d, %d)" % (w, h))
        dpival = self.figure.dpi
        winch = w / dpival
        hinch = h / dpival
        self.figure.set_size_inches(winch, hinch, forward=False)
        FigureCanvasBase.resize_event(self)
        self.draw_idle()
        QtWidgets.QWidget.resizeEvent(self, event)

    def sizeHint(self):
        w, h = self.get_width_height()
        return QtCore.QSize(w, h)

    def minumumSizeHint(self):
        return QtCore.QSize(10, 10)

    def _get_key(self, event):
        if not self._keyautorepeat and event.isAutoRepeat():
            return None

        event_key = event.key()
        event_mods = int(event.modifiers())  # actually a bitmask

        # get names of the pressed modifier keys
        # bit twiddling to pick out modifier keys from event_mods bitmask,
        # if event_key is a MODIFIER, it should not be duplicated in mods
        mods = [name for name, mod_key, qt_key in MODIFIER_KEYS
                if event_key != qt_key and (event_mods & mod_key) == mod_key]
        try:
            # for certain keys (enter, left, backspace, etc) use a word for the
            # key, rather than unicode
            key = SPECIAL_KEYS[event_key]
        except KeyError:
            # unicode defines code points up to 0x0010ffff
            # QT will use Key_Codes larger than that for keyboard keys that are
            # are not unicode characters (like multimedia keys)
            # skip these
            # if you really want them, you should add them to SPECIAL_KEYS
            MAX_UNICODE = 0x10ffff
            if event_key > MAX_UNICODE:
                return None

            key = unichr(event_key)
            # qt delivers capitalized letters.  fix capitalization
            # note that capslock is ignored
            if 'shift' in mods:
                mods.remove('shift')
            else:
                key = key.lower()

        mods.reverse()
        return '+'.join(mods + [key])

    def new_timer(self, *args, **kwargs):
        """
        Creates a new backend-specific subclass of
        :class:`backend_bases.Timer`.  This is useful for getting
        periodic events through the backend's native event
        loop. Implemented only for backends with GUIs.

        Other Parameters
        ----------------
        interval : scalar
            Timer interval in milliseconds

        callbacks : list
            Sequence of (func, args, kwargs) where ``func(*args, **kwargs)``
            will be executed by the timer every *interval*.

        """
        return TimerQT(*args, **kwargs)

    def flush_events(self):
        global qApp
        qApp.processEvents()

    def start_event_loop(self, timeout):
        FigureCanvasBase.start_event_loop_default(self, timeout)

    start_event_loop.__doc__ = \
                             FigureCanvasBase.start_event_loop_default.__doc__

    def stop_event_loop(self):
        FigureCanvasBase.stop_event_loop_default(self)

    stop_event_loop.__doc__ = FigureCanvasBase.stop_event_loop_default.__doc__


class MainWindow(QtWidgets.QMainWindow):
    closing = QtCore.Signal()

    def closeEvent(self, event):
        self.closing.emit()
        QtWidgets.QMainWindow.closeEvent(self, event)


class FigureManagerQT(FigureManagerBase):
    """
    Attributes
    ----------
    canvas : `FigureCanvas`
        The FigureCanvas instance
    num : int or str
        The Figure number
    toolbar : qt.QToolBar
        The qt.QToolBar
    window : qt.QMainWindow
        The qt.QMainWindow

    """

    def __init__(self, canvas, num):
        if DEBUG:
            print('FigureManagerQT.%s' % fn_name())
        FigureManagerBase.__init__(self, canvas, num)
        self.canvas = canvas
        self.window = MainWindow()
        self.window.closing.connect(canvas.close_event)
        self.window.closing.connect(self._widgetclosed)

        self.window.setWindowTitle("Figure %d" % num)
        image = os.path.join(matplotlib.rcParams['datapath'],
                             'images', 'matplotlib.png')
        self.window.setWindowIcon(QtGui.QIcon(image))

        # Give the keyboard focus to the figure instead of the
        # manager; StrongFocus accepts both tab and click to focus and
        # will enable the canvas to process event w/o clicking.
        # ClickFocus only takes the focus is the window has been
        # clicked
        # on. http://qt-project.org/doc/qt-4.8/qt.html#FocusPolicy-enum or
        # http://doc.qt.digia.com/qt/qt.html#FocusPolicy-enum
        self.canvas.setFocusPolicy(QtCore.Qt.StrongFocus)
        self.canvas.setFocus()

        self.window._destroying = False

        # add text label to status bar
        self.statusbar_label = QtWidgets.QLabel()
        self.window.statusBar().addWidget(self.statusbar_label)

        self.toolbar = self._get_toolbar(self.canvas, self.window)
        if self.toolbar is not None:
            self.window.addToolBar(self.toolbar)
            self.toolbar.message.connect(self.statusbar_label.setText)
            tbs_height = self.toolbar.sizeHint().height()
        else:
            tbs_height = 0

        # resize the main window so it will display the canvas with the
        # requested size:
        cs = canvas.sizeHint()
        sbs = self.window.statusBar().sizeHint()
        self._status_and_tool_height = tbs_height + sbs.height()
        height = cs.height() + self._status_and_tool_height
        self.window.resize(cs.width(), height)

        self.window.setCentralWidget(self.canvas)

        if matplotlib.is_interactive():
            self.window.show()
            self.canvas.draw_idle()

        def notify_axes_change(fig):
            # This will be called whenever the current axes is changed
            if self.toolbar is not None:
                self.toolbar.update()
        self.canvas.figure.add_axobserver(notify_axes_change)
        self.window.raise_()

    def full_screen_toggle(self):
        if self.window.isFullScreen():
            self.window.showNormal()
        else:
            self.window.showFullScreen()

    def _widgetclosed(self):
        if self.window._destroying:
            return
        self.window._destroying = True
        try:
            Gcf.destroy(self.num)
        except AttributeError:
            pass
            # It seems that when the python session is killed,
            # Gcf can get destroyed before the Gcf.destroy
            # line is run, leading to a useless AttributeError.

    def _get_toolbar(self, canvas, parent):
        # must be inited after the window, drawingArea and figure
        # attrs are set
        if matplotlib.rcParams['toolbar'] == 'toolbar2':
            toolbar = NavigationToolbar2QT(canvas, parent, False)
        else:
            toolbar = None
        return toolbar

    def resize(self, width, height):
        'set the canvas size in pixels'
        self.window.resize(width, height + self._status_and_tool_height)

    def show(self):
        self.window.show()

    def destroy(self, *args):
        # check for qApp first, as PySide deletes it in its atexit handler
        if QtWidgets.QApplication.instance() is None:
            return
        if self.window._destroying:
            return
        self.window._destroying = True
        self.window.destroyed.connect(self._widgetclosed)

        if self.toolbar:
            self.toolbar.destroy()
        if DEBUG:
            print("destroy figure manager")
        self.window.close()

    def get_window_title(self):
        return six.text_type(self.window.windowTitle())

    def set_window_title(self, title):
        self.window.setWindowTitle(title)


class NavigationToolbar2QT(NavigationToolbar2, QtWidgets.QToolBar):
    message = QtCore.Signal(str)

    def __init__(self, canvas, parent, coordinates=True):
        """ coordinates: should we show the coordinates on the right? """
        self.canvas = canvas
        self.parent = parent
        self.coordinates = coordinates
        self._actions = {}
        """A mapping of toolitem method names to their QActions"""

        QtWidgets.QToolBar.__init__(self, parent)
        NavigationToolbar2.__init__(self, canvas)

    def _icon(self, name):
        if is_pyqt5():
            name = name.replace('.png', '_large.png')
        return QtGui.QIcon(os.path.join(self.basedir, name))

    def _init_toolbar(self):
        self.basedir = os.path.join(matplotlib.rcParams['datapath'], 'images')

        for text, tooltip_text, image_file, callback in self.toolitems:
            if text is None:
                self.addSeparator()
            else:
                a = self.addAction(self._icon(image_file + '.png'),
                                         text, getattr(self, callback))
                self._actions[callback] = a
                if callback in ['zoom', 'pan']:
                    a.setCheckable(True)
                if tooltip_text is not None:
                    a.setToolTip(tooltip_text)
                if text == 'Subplots':
                    a = self.addAction(self._icon("qt4_editor_options.png"),
                                       'Customize', self.edit_parameters)
                    a.setToolTip('Edit axis, curve and image parameters')

        self.buttons = {}

        # Add the x,y location widget at the right side of the toolbar
        # The stretch factor is 1 which means any resizing of the toolbar
        # will resize this label instead of the buttons.
        if self.coordinates:
            self.locLabel = QtWidgets.QLabel("", self)
            self.locLabel.setAlignment(
                    QtCore.Qt.AlignRight | QtCore.Qt.AlignTop)
            self.locLabel.setSizePolicy(
                QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding,
                                  QtWidgets.QSizePolicy.Ignored))
            labelAction = self.addWidget(self.locLabel)
            labelAction.setVisible(True)

        # reference holder for subplots_adjust window
        self.adj_window = None

        # Esthetic adjustments - we need to set these explicitly in PyQt5
        # otherwise the layout looks different - but we don't want to set it if
        # not using HiDPI icons otherwise they look worse than before.
        if is_pyqt5():
            self.setIconSize(QtCore.QSize(24, 24))
            self.layout().setSpacing(12)

    if is_pyqt5():
        # For some reason, self.setMinimumHeight doesn't seem to carry over to
        # the actual sizeHint, so override it instead in order to make the
        # aesthetic adjustments noted above.
        def sizeHint(self):
            size = super(NavigationToolbar2QT, self).sizeHint()
            size.setHeight(max(48, size.height()))
            return size

    def edit_parameters(self):
        allaxes = self.canvas.figure.get_axes()
        if not allaxes:
            QtWidgets.QMessageBox.warning(
                self.parent, "Error", "There are no axes to edit.")
            return
        if len(allaxes) == 1:
            axes = allaxes[0]
        else:
            titles = []
            for axes in allaxes:
                name = (axes.get_title() or
                        " - ".join(filter(None, [axes.get_xlabel(),
                                                 axes.get_ylabel()])) or
                        "<anonymous {} (id: {:#x})>".format(
                            type(axes).__name__, id(axes)))
                titles.append(name)
            item, ok = QtWidgets.QInputDialog.getItem(
                self.parent, 'Customize', 'Select axes:', titles, 0, False)
            if ok:
                axes = allaxes[titles.index(six.text_type(item))]
            else:
                return

        figureoptions.figure_edit(axes, self)

    def _update_buttons_checked(self):
        # sync button checkstates to match active mode
        self._actions['pan'].setChecked(self._active == 'PAN')
        self._actions['zoom'].setChecked(self._active == 'ZOOM')

    def pan(self, *args):
        super(NavigationToolbar2QT, self).pan(*args)
        self._update_buttons_checked()

    def zoom(self, *args):
        super(NavigationToolbar2QT, self).zoom(*args)
        self._update_buttons_checked()

    def dynamic_update(self):
        self.canvas.draw_idle()

    def set_message(self, s):
        self.message.emit(s)
        if self.coordinates:
            self.locLabel.setText(s)

    def set_cursor(self, cursor):
        if DEBUG:
            print('Set cursor', cursor)
        self.canvas.setCursor(cursord[cursor])

    def draw_rubberband(self, event, x0, y0, x1, y1):
        height = self.canvas.figure.bbox.height
        y1 = height - y1
        y0 = height - y0

        w = abs(x1 - x0)
        h = abs(y1 - y0)

        rect = [int(val)for val in (min(x0, x1), min(y0, y1), w, h)]
        self.canvas.drawRectangle(rect)

    def remove_rubberband(self):
        self.canvas.drawRectangle(None)

    def configure_subplots(self):
        image = os.path.join(matplotlib.rcParams['datapath'],
                             'images', 'matplotlib.png')
        dia = SubplotToolQt(self.canvas.figure, self.parent)
        dia.setWindowIcon(QtGui.QIcon(image))
        dia.exec_()

    def save_figure(self, *args):
        filetypes = self.canvas.get_supported_filetypes_grouped()
        sorted_filetypes = sorted(six.iteritems(filetypes))
        default_filetype = self.canvas.get_default_filetype()

        startpath = matplotlib.rcParams.get('savefig.directory', '')
        startpath = os.path.expanduser(startpath)
        start = os.path.join(startpath, self.canvas.get_default_filename())
        filters = []
        selectedFilter = None
        for name, exts in sorted_filetypes:
            exts_list = " ".join(['*.%s' % ext for ext in exts])
            filter = '%s (%s)' % (name, exts_list)
            if default_filetype in exts:
                selectedFilter = filter
            filters.append(filter)
        filters = ';;'.join(filters)

        fname, filter = _getSaveFileName(self.parent,
                                         "Choose a filename to save to",
                                 start, filters, selectedFilter)
        if fname:
            if startpath == '':
                # explicitly missing key or empty str signals to use cwd
                matplotlib.rcParams['savefig.directory'] = startpath
            else:
                # save dir for next time
                savefig_dir = os.path.dirname(six.text_type(fname))
                matplotlib.rcParams['savefig.directory'] = savefig_dir
            try:
                self.canvas.print_figure(six.text_type(fname))
            except Exception as e:
                QtWidgets.QMessageBox.critical(
                    self, "Error saving file", six.text_type(e),
                    QtWidgets.QMessageBox.Ok, QtWidgets.QMessageBox.NoButton)


class SubplotToolQt(SubplotTool, UiSubplotTool):
    def __init__(self, targetfig, parent):
        UiSubplotTool.__init__(self, None)

        self.targetfig = targetfig
        self.parent = parent
        self.donebutton.clicked.connect(self.close)
        self.resetbutton.clicked.connect(self.reset)
        self.tightlayout.clicked.connect(self.functight)

        # constraints
        self.sliderleft.valueChanged.connect(self.sliderright.setMinimum)
        self.sliderright.valueChanged.connect(self.sliderleft.setMaximum)
        self.sliderbottom.valueChanged.connect(self.slidertop.setMinimum)
        self.slidertop.valueChanged.connect(self.sliderbottom.setMaximum)

        self.defaults = {}
        for attr in ('left', 'bottom', 'right', 'top', 'wspace', 'hspace', ):
            val = getattr(self.targetfig.subplotpars, attr)
            self.defaults[attr] = val
            slider = getattr(self, 'slider' + attr)
            txt = getattr(self, attr + 'value')
            slider.setMinimum(0)
            slider.setMaximum(1000)
            slider.setSingleStep(5)
            # do this before hooking up the callbacks
            slider.setSliderPosition(int(val * 1000))
            txt.setText("%.2f" % val)
            slider.valueChanged.connect(getattr(self, 'func' + attr))
        self._setSliderPositions()

    def _setSliderPositions(self):
        for attr in ('left', 'bottom', 'right', 'top', 'wspace', 'hspace', ):
            slider = getattr(self, 'slider' + attr)
            slider.setSliderPosition(int(self.defaults[attr] * 1000))

    def funcleft(self, val):
        if val == self.sliderright.value():
            val -= 1
        val /= 1000.
        self.targetfig.subplots_adjust(left=val)
        self.leftvalue.setText("%.2f" % val)
        if self.drawon:
            self.targetfig.canvas.draw_idle()

    def funcright(self, val):
        if val == self.sliderleft.value():
            val += 1
        val /= 1000.
        self.targetfig.subplots_adjust(right=val)
        self.rightvalue.setText("%.2f" % val)
        if self.drawon:
            self.targetfig.canvas.draw_idle()

    def funcbottom(self, val):
        if val == self.slidertop.value():
            val -= 1
        val /= 1000.
        self.targetfig.subplots_adjust(bottom=val)
        self.bottomvalue.setText("%.2f" % val)
        if self.drawon:
            self.targetfig.canvas.draw_idle()

    def functop(self, val):
        if val == self.sliderbottom.value():
            val += 1
        val /= 1000.
        self.targetfig.subplots_adjust(top=val)
        self.topvalue.setText("%.2f" % val)
        if self.drawon:
            self.targetfig.canvas.draw_idle()

    def funcwspace(self, val):
        val /= 1000.
        self.targetfig.subplots_adjust(wspace=val)
        self.wspacevalue.setText("%.2f" % val)
        if self.drawon:
            self.targetfig.canvas.draw_idle()

    def funchspace(self, val):
        val /= 1000.
        self.targetfig.subplots_adjust(hspace=val)
        self.hspacevalue.setText("%.2f" % val)
        if self.drawon:
            self.targetfig.canvas.draw_idle()

    def functight(self):
        self.targetfig.tight_layout()
        self._setSliderPositions()
        self.targetfig.canvas.draw_idle()

    def reset(self):
        self.targetfig.subplots_adjust(**self.defaults)
        self._setSliderPositions()
        self.targetfig.canvas.draw_idle()


def error_msg_qt(msg, parent=None):
    if not isinstance(msg, six.string_types):
        msg = ','.join(map(str, msg))

    QtWidgets.QMessageBox.warning(None, "Matplotlib",
                                  msg, QtGui.QMessageBox.Ok)


def exception_handler(type, value, tb):
    """Handle uncaught exceptions
    It does not catch SystemExit
    """
    msg = ''
    # get the filename attribute if available (for IOError)
    if hasattr(value, 'filename') and value.filename is not None:
        msg = value.filename + ': '
    if hasattr(value, 'strerror') and value.strerror is not None:
        msg += value.strerror
    else:
        msg += six.text_type(value)

    if len(msg):
        error_msg_qt(msg)

FigureCanvas = FigureCanvasQT
FigureManager = FigureManagerQT
